Car-spring



(N0 Mbdel.) L. PPINGST.

OAR SPRING-v No. 485,652. Patented Nov. 8, 1892.

UNITED STATES PATENT OFFICE.

LOUIS PFINGST, OF BOSTON, MASSACHUSETTS.

CAR-SPRING.

SPECIFICATION forming part of Letters Patent No. 485,652, dated November8, 1892.

Application filed May 23, 1892 To all whom it may concern:

Be it known that I, LOUIS PFINGST, of Boston, in the county of Suffolk,State of Massachusetts, have invented certain new and usefulImprovements in Oar-Springs, of which the following is a descriptionsufficiently full, clear, and exact to enable any person skilled in theart or science to which said invention appertains to make and use thesame, reference being bad to the accompanying drawings, forming part ofthis specification, in which Figure l is an elevation of my improvedcarspring; Fig.2, a like view showing the spring partly compressed; Fig.3,across'-section taken on line :0 a; in Fig. 1, and Fig. 4 aplan viewof the rod from which the spring is Wound.

Like letters of reference indicate corresponding parts in the differentfigures of the drawings.

My invention relates to a supporting-spring for railway-cars and similarvehicles, it being designed especially as an improvement on the springshown and described in my United States Letters Patent No. 462,958,dated November 10, 1891, granted to me for an improvement incar-springs, the object being particularly to render the springcorrespondingly sensitive as the load on the vehicle varies.

In the drawings, A represents the spring considered as a Whole. Informing the spring I employ a rod circular in cross-section and of equaldiameter from one end 01 to a predetermined point f, preferably at oradjacent the longitudinal center of the rod. From said point f the rodtapers gradually and continuously throughout, its diameter decreasing tothe opposite end g, at which point it is of the smallest diameter. Thatportion h of the rod from the end at to the middle point f of the .samediameter throughout forms the base B when wound, and the taper portion'5 forms the top 0. The rod is wound on a mandrel of equal diameterthroughout. This forms a Serial No. 434,044. (No model.)

coil of equal interior diameter, the exterior diameter of the top 0 ofthe coil gradually decreasing from the base portion to its end, as

best shown in Fig. 2. In this form of spring the top 0 is much stifferthan in the form described in the Letters Patent above referred to, andwhen the load is applied to it the coils compress successively,beginning at the top, its expansive properties being much the same inefiect as a conical spring, but the graduated stiffness being attainedby tapering the bar, as described. Under a light load the top 0 servesto cushion, while the base B resists compression; but before the top hasbeen strained nearits limit said base willbegin to compress, cushioningany increase of load,the top coils assuming the closed position shown inFig. 2. The base, moreover, being of equal diameter and the upperportion being tapered, as described, the oscillation of the vehicle-bodyis greatly reduced.

It will be understood that the portions of the rod composing the baseand top may be varied in length in relation to each other in any mannerdesired.

Having thus explained my invention, what I claim is- I A springcomprising a spirally-Wound rod, that portion of the rod forming thelower portion of the spring being of one size throughout and wound withits interior and exterior diameters, respectively, equal throughout, andthat'portion of the rod forming the upper portion of the spring beingtapered from its point of connection with the lower portion continuouslythroughout, the interior diameter of the spiral coils of both upper andlower portions being uniform throughout the entire spring and theexterior diameter of the lower portion being greater than that of theupper portion.

LOUIS PFINGST. Witnesses:

O. M. SHAW, K. DURFEE.

